/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.test.operators;

import org.apache.flink.api.common.functions.FlatMapFunction;
import org.apache.flink.api.common.functions.RichFlatMapFunction;
import org.apache.flink.api.java.DataSet;
import org.apache.flink.api.java.ExecutionEnvironment;
import org.apache.flink.api.java.tuple.Tuple3;
import org.apache.flink.configuration.Configuration;
import org.apache.flink.test.operators.util.CollectionDataSets;
import org.apache.flink.test.operators.util.CollectionDataSets.CustomType;
import org.apache.flink.test.util.MultipleProgramsTestBase;
import org.apache.flink.util.Collector;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;

import java.util.Collection;
import java.util.List;

/**
 * Integration tests for {@link FlatMapFunction} and {@link RichFlatMapFunction}.
 */
@RunWith(Parameterized.class)
public class FlatMapITCase extends MultipleProgramsTestBase {
	public FlatMapITCase(TestExecutionMode mode){
		super(mode);
	}

	@Test
	public void testNonPassingFlatMap() throws Exception {
		/*
		 * Test non-passing flatmap
		 */

		final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();

		DataSet<String> ds = CollectionDataSets.getStringDataSet(env);
		DataSet<String> nonPassingFlatMapDs = ds.
				flatMap(new FlatMapper1());

		List<String> result = nonPassingFlatMapDs.collect();

		String expected = "\n";

		compareResultAsText(result, expected);
	}

	private static class FlatMapper1 implements FlatMapFunction<String, String> {
		private static final long serialVersionUID = 1L;

		@Override
		public void flatMap(String value, Collector<String> out) throws Exception {
			if (value.contains("bananas")) {
				out.collect(value);
			}
		}
	}

	@Test
	public void testDataDuplicatingFlatMap() throws Exception {
		/*
		 * Test data duplicating flatmap
		 */

		final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();

		DataSet<String> ds = CollectionDataSets.getStringDataSet(env);
		DataSet<String> duplicatingFlatMapDs = ds.
				flatMap(new FlatMapper2());

		List<String> result = duplicatingFlatMapDs.collect();

		String expected = "Hi\n" + "HI\n" +
				"Hello\n" + "HELLO\n" +
				"Hello world\n" + "HELLO WORLD\n" +
				"Hello world, how are you?\n" + "HELLO WORLD, HOW ARE YOU?\n" +
				"I am fine.\n" + "I AM FINE.\n" +
				"Luke Skywalker\n" + "LUKE SKYWALKER\n" +
				"Random comment\n" + "RANDOM COMMENT\n" +
				"LOL\n" + "LOL\n";

		compareResultAsText(result, expected);
	}

	private static class FlatMapper2 implements FlatMapFunction<String, String> {
		private static final long serialVersionUID = 1L;

		@Override
		public void flatMap(String value, Collector<String> out) throws Exception {
			out.collect(value);
			out.collect(value.toUpperCase());
		}
	}

	@Test
	public void testFlatMapWithVaryingNumberOfEmittedTuples() throws Exception {
		/*
		 * Test flatmap with varying number of emitted tuples
		 */

		final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();

		DataSet<Tuple3<Integer, Long, String>> ds = CollectionDataSets.get3TupleDataSet(env);
		DataSet<Tuple3<Integer, Long, String>> varyingTuplesMapDs = ds.
				flatMap(new FlatMapper3());

		List<Tuple3<Integer, Long, String>> result = varyingTuplesMapDs.collect();

		String expected = "1,1,Hi\n" +
				"2,2,Hello\n" + "2,2,Hello\n" +
				"4,3,Hello world, how are you?\n" +
				"5,3,I am fine.\n" + "5,3,I am fine.\n" +
				"7,4,Comment#1\n" +
				"8,4,Comment#2\n" + "8,4,Comment#2\n" +
				"10,4,Comment#4\n" +
				"11,5,Comment#5\n" + "11,5,Comment#5\n" +
				"13,5,Comment#7\n" +
				"14,5,Comment#8\n" + "14,5,Comment#8\n" +
				"16,6,Comment#10\n" +
				"17,6,Comment#11\n" + "17,6,Comment#11\n" +
				"19,6,Comment#13\n" +
				"20,6,Comment#14\n" + "20,6,Comment#14\n";

		compareResultAsTuples(result, expected);
	}

	private static class FlatMapper3 implements FlatMapFunction<Tuple3<Integer, Long, String>, Tuple3<Integer, Long, String>> {
		private static final long serialVersionUID = 1L;

		@Override
		public void flatMap(Tuple3<Integer, Long, String> value,
				Collector<Tuple3<Integer, Long, String>> out) throws Exception {
			final int numTuples = value.f0 % 3;
			for (int i = 0; i < numTuples; i++) {
				out.collect(value);
			}
		}
	}

	@Test
	public void testTypeConversionFlatMapperCustomToTuple() throws Exception {
		/*
		 * Test type conversion flatmapper (Custom -> Tuple)
		 */

		final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();

		DataSet<CustomType> ds = CollectionDataSets.getCustomTypeDataSet(env);
		DataSet<Tuple3<Integer, Long, String>> typeConversionFlatMapDs = ds.
				flatMap(new FlatMapper4());

		List<Tuple3<Integer, Long, String>> result = typeConversionFlatMapDs.collect();

		String expected = "1,0,Hi\n" +
				"2,1,Hello\n" +
				"2,2,Hello world\n" +
				"3,3,Hello world, how are you?\n" +
				"3,4,I am fine.\n" +
				"3,5,Luke Skywalker\n" +
				"4,6,Comment#1\n" +
				"4,7,Comment#2\n" +
				"4,8,Comment#3\n" +
				"4,9,Comment#4\n" +
				"5,10,Comment#5\n" +
				"5,11,Comment#6\n" +
				"5,12,Comment#7\n" +
				"5,13,Comment#8\n" +
				"5,14,Comment#9\n" +
				"6,15,Comment#10\n" +
				"6,16,Comment#11\n" +
				"6,17,Comment#12\n" +
				"6,18,Comment#13\n" +
				"6,19,Comment#14\n" +
				"6,20,Comment#15\n";

		compareResultAsTuples(result, expected);
	}

	private static class FlatMapper4 implements FlatMapFunction<CustomType, Tuple3<Integer, Long, String>> {
		private static final long serialVersionUID = 1L;
		private final Tuple3<Integer, Long, String> outTuple =
				new Tuple3<Integer, Long, String>();

		@Override
		public void flatMap(CustomType value, Collector<Tuple3<Integer, Long, String>> out) throws Exception {
			outTuple.setField(value.myInt, 0);
			outTuple.setField(value.myLong, 1);
			outTuple.setField(value.myString, 2);
			out.collect(outTuple);
		}
	}

	@Test
	public void testTypeConversionFlatMapperTupleToBasic() throws Exception {
		/*
		 * Test type conversion flatmapper (Tuple -> Basic)
		 */

		final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();

		DataSet<Tuple3<Integer, Long, String>> ds = CollectionDataSets.get3TupleDataSet(env);
		DataSet<String> typeConversionFlatMapDs = ds.
				flatMap(new FlatMapper5());

		List<String> result = typeConversionFlatMapDs.collect();

		String expected = "Hi\n" + "Hello\n" + "Hello world\n"
				+
				"Hello world, how are you?\n" +
				"I am fine.\n" + "Luke Skywalker\n" +
				"Comment#1\n" +	"Comment#2\n" +
				"Comment#3\n" +	"Comment#4\n" +
				"Comment#5\n" +	"Comment#6\n" +
				"Comment#7\n" + "Comment#8\n" +
				"Comment#9\n" +	"Comment#10\n" +
				"Comment#11\n" + "Comment#12\n" +
				"Comment#13\n" + "Comment#14\n" +
				"Comment#15\n";

		compareResultAsText(result, expected);
	}

	private static class FlatMapper5 implements FlatMapFunction<Tuple3<Integer, Long, String>, String> {
		private static final long serialVersionUID = 1L;

		@Override
		public void flatMap(Tuple3<Integer, Long, String> value, Collector<String> out) throws Exception {
			out.collect(value.f2);
		}
	}

	@Test
	public void testFlatMapperIfUDFReturnsInputObjectMultipleTimesWhileChangingIt() throws Exception {
		/*
		 * Test flatmapper if UDF returns input object
		 * multiple times and changes it in between
		 */

		final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();

		DataSet<Tuple3<Integer, Long, String>> ds = CollectionDataSets.get3TupleDataSet(env);
		DataSet<Tuple3<Integer, Long, String>> inputObjFlatMapDs = ds.
				flatMap(new FlatMapper6());

		List<Tuple3<Integer, Long, String>> result = inputObjFlatMapDs.collect();

		String expected = "0,1,Hi\n" +
				"0,2,Hello\n" + "1,2,Hello\n" +
				"0,2,Hello world\n" + "1,2,Hello world\n" + "2,2,Hello world\n" +
				"0,3,I am fine.\n" +
				"0,3,Luke Skywalker\n" + "1,3,Luke Skywalker\n" +
				"0,4,Comment#1\n" + "1,4,Comment#1\n" + "2,4,Comment#1\n" +
				"0,4,Comment#3\n" +
				"0,4,Comment#4\n" + "1,4,Comment#4\n" +
				"0,5,Comment#5\n" + "1,5,Comment#5\n" + "2,5,Comment#5\n" +
				"0,5,Comment#7\n" +
				"0,5,Comment#8\n" + "1,5,Comment#8\n" +
				"0,5,Comment#9\n" + "1,5,Comment#9\n" + "2,5,Comment#9\n" +
				"0,6,Comment#11\n" +
				"0,6,Comment#12\n" + "1,6,Comment#12\n" +
				"0,6,Comment#13\n" + "1,6,Comment#13\n" + "2,6,Comment#13\n" +
				"0,6,Comment#15\n";

		compareResultAsTuples(result, expected);
	}

	private static class FlatMapper6 implements FlatMapFunction<Tuple3<Integer, Long, String>, Tuple3<Integer, Long, String>> {
		private static final long serialVersionUID = 1L;

		@Override
		public void flatMap(Tuple3<Integer, Long, String> value,
				Collector<Tuple3<Integer, Long, String>> out) throws Exception {
			final int numTuples = value.f0 % 4;
			for (int i = 0; i < numTuples; i++) {
				value.setField(i, 0);
				out.collect(value);
			}
		}
	}

	@Test
	public void testFlatMapWithBroadcastSet() throws Exception {
		/*
		 * Test flatmap with broadcast set
		 */

		final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();

		DataSet<Integer> ints = CollectionDataSets.getIntegerDataSet(env);

		DataSet<Tuple3<Integer, Long, String>> ds = CollectionDataSets.get3TupleDataSet(env);
		DataSet<Tuple3<Integer, Long, String>> bcFlatMapDs = ds.
				flatMap(new RichFlatMapper1()).withBroadcastSet(ints, "ints");
		List<Tuple3<Integer, Long, String>> result = bcFlatMapDs.collect();

		String expected = "55,1,Hi\n" +
				"55,2,Hello\n" +
				"55,2,Hello world\n" +
				"55,3,Hello world, how are you?\n" +
				"55,3,I am fine.\n" +
				"55,3,Luke Skywalker\n" +
				"55,4,Comment#1\n" +
				"55,4,Comment#2\n" +
				"55,4,Comment#3\n" +
				"55,4,Comment#4\n" +
				"55,5,Comment#5\n" +
				"55,5,Comment#6\n" +
				"55,5,Comment#7\n" +
				"55,5,Comment#8\n" +
				"55,5,Comment#9\n" +
				"55,6,Comment#10\n" +
				"55,6,Comment#11\n" +
				"55,6,Comment#12\n" +
				"55,6,Comment#13\n" +
				"55,6,Comment#14\n" +
				"55,6,Comment#15\n";

		compareResultAsTuples(result, expected);
	}

	private static class RichFlatMapper1 extends RichFlatMapFunction<Tuple3<Integer, Long, String>, Tuple3<Integer, Long, String>> {
		private static final long serialVersionUID = 1L;
		private final Tuple3<Integer, Long, String> outTuple =
				new Tuple3<Integer, Long, String>();
		private Integer f2Replace = 0;

		@Override
		public void open(Configuration config) {
			Collection<Integer> ints = this.getRuntimeContext().getBroadcastVariable("ints");
			int sum = 0;
			for (Integer i : ints) {
				sum += i;
			}
			f2Replace = sum;
		}

		@Override
		public void flatMap(Tuple3<Integer, Long, String> value,
				Collector<Tuple3<Integer, Long, String>> out) throws Exception {
			outTuple.setFields(f2Replace, value.f1, value.f2);
			out.collect(outTuple);
		}
	}

}
